package test;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;

public class test {
    public static void main(String[] args) {
        ArrayList<String> strings = new ArrayList<String>();
        ArrayList<ArrayList<String>> res = new ArrayList<ArrayList<String>>();

        Collections.sort(res, (o1,o2) ->o1.get(0).length()-o2.get(0).length());
    }
}
